The present invention relates to a gas-liquid separator for a fuel cell system onboard a vehicle, which separates water contained in its exhaust gas.
Generally speaking, individual cells are bundled together to form a fuel cell stack, each of which has a cathode and anode separated by a proton conductive polymer electrolyte membrane (PEM). An individual cell generates electric power by electrochemical reaction between oxygen contained in air which is supplied to a cathode and hydrogen contained in fuel gas which is supplied to an anode. In this connection, a gas-liquid separator has been known which separates water in exhaust gas discharged by a fuel cell stack (See patent document 1). Because the water in the exhaust gas is separated by the gas-liquid separator, it is possible to prevent the water from staying in a line for circulating the exhaust gas. Therefore, the gas-liquid separator helps bring about smooth transportation of the exhaust gas in a downstream direction.
Patent document 1: Japanese Published Patent Application 2002-352844 (paragraphs 0023-0028 and FIG. 1)
A fuel cell vehicle, which is powered by electricity generated by a fuel cell system, has been drawing attention recently. It is desirable to adopt a gas-liquid separator for the fuel cell system onboard the vehicle, which is adapted to be low in height so as to be compatible with a space provided in the vehicle. As an example of this, a gas-liquid separator may be listed, in which pipes such as a pipe for circulating exhaust gas (inlet pipe and outlet pipe), a drain pipe and the like are attached to side walls of the separator.
When the fuel cell vehicle tilts, the gas-liquid separator tilts accordingly. As a result, water separated from the exhaust gas migrates in the gas-liquid separator, concentrating locally close to a side wall. In this way, it may be possible that the water flows into the pipe for circulating exhaust gas, causing an adverse effect of blockage.